Class: CryptoArbitrer::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/crypto_arbitrer.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.btc_usd_strategy ⇒ Object 



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# File 'lib/crypto_arbitrer.rb', line 8

def self.btc_usd_strategy
  @btc_usd_strategy || :mtgox
end

.btc_usd_strategy=(strategy) ⇒ Object 



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# File 'lib/crypto_arbitrer.rb', line 12

def self.btc_usd_strategy=(strategy)
  @btc_usd_strategy = strategy
end

.cache_backend ⇒ Object 



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# File 'lib/crypto_arbitrer.rb', line 47

def cache_backend
  @cache_backend
end

.cache_backend=(backend) ⇒ Object

If you want to cache calls done to third party api’s you should use this. Pass in a lambda that will receive the cache key name and the block for fetching it’s value. If you’re using rails you can configure CryptoArbitrer in an initializer to use rails caching just forwarding the cache key and the block to it. You can set the cache_backend to nil to prevent caching (not recommended, unless you’re testing)



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# File 'lib/crypto_arbitrer.rb', line 43

def cache_backend=(backend)
  @cache_backend = backend
end

.derive_reversal(from, to) ⇒ Object

For existing known exchange rates, we want to derive the reverse lookup, for example: We derive ars_usd from usd_ars



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# File 'lib/crypto_arbitrer.rb', line 54

def self.derive_reversal(from, to)
  define_method("fetch_#{to}_#{from}") do
    rate = send("fetch_#{from}_#{to}")
    {'sell' => 1/rate['sell'], 'buy' => 1/rate['buy']}
  end
end

.fetch(from, to, force = false) ⇒ {'buy' => Float, 'sell' => Float}

Fetch a given conversion caching the result if a backend is set. This should be the preferred way to fetch a conversion by users. Check #supported_currencies for a list of possible values for ‘from’ and ‘to’

Parameters:

  • from (String) —

    a three letter currency code to convert from.

  • to (String) —

    a three letter currency code to convert to.

  • to (String) —

    a three letter currency code to convert to.

  • force (Boolean) (defaults to: false) —

    Ignore the cache (does not read from it, and does not write to it). Defaults to false.

Returns:

  • ({'buy' => Float, 'sell' => Float}) —

    The buy and sell prices



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# File 'lib/crypto_arbitrer.rb', line 177

def self.fetch(from,to, force = false)
  new.fetch(from.downcase, to.downcase, force)
end

.supported_conversions ⇒ Object

Quasi constant, a list of iso code pairs representing all supported exchange rates.

[‘ars’,‘usd’],,[‘ltc’,‘cnc’],… 


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# File 'lib/crypto_arbitrer.rb', line 33

def self.supported_conversions
  supported_currencies.product(supported_currencies)
end

.supported_cryptos ⇒ Object

Quasi constant, all supported crypto currencies.



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# File 'lib/crypto_arbitrer.rb', line 22

def self.supported_cryptos
  %w(btc ltc nmc nvc trc ppc ftc cnc)
end

.supported_currencies ⇒ Object

Quasi constant, all supported currencies.



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# File 'lib/crypto_arbitrer.rb', line 27

def self.supported_currencies
  supported_fiat + supported_cryptos
end

.supported_fiat ⇒ Object

Quasi constant, all supported fiat currencies.



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# File 'lib/crypto_arbitrer.rb', line 17

def self.supported_fiat
  %w(usd ars uyu brl clp sgd eur vef)
end

Instance Method Details

#fetch(from, to, force = false) ⇒ Object 



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# File 'lib/crypto_arbitrer.rb', line 161

def fetch(from, to, force = false)
  if force
    send("fetch_#{from}_#{to}")
  else
    cached(from, to){ send("fetch_#{from}_#{to}") }
  end
end

#fetch_btc_usd ⇒ Object

Uses mt.gox API for checking latest bitcoin sell and buy prices. The returned hash has ‘sell’ and ‘buy’ keys for the different prices, the prices mean at which price you could buy and sell from them, respectively.



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# File 'lib/crypto_arbitrer.rb', line 78

def fetch_btc_usd
  if self.class.btc_usd_strategy == :mtgox
    response = open('http://data.mtgox.com/api/2/BTCUSD/money/ticker_fast').read
    json = JSON.parse(response)['data']
    {'sell' => json['sell']['value'].to_f, 'buy' => json['buy']['value'].to_f}
  else
    parse_btce_prices open("https://btc-e.com/exchange/btc_usd").read
  end
end

#fetch_usd_ars ⇒ Object

Uses eldolarblue.net API for checking Argentine unofficial US dolar prices. The returned hash has ‘sell’ and ‘buy’ keys for the different prices. ‘buy’ is the price at which you can buy USD from agents and ‘sell’ is the price at which you can sell USD to agents. Notice this is the opposite to argentina’s convention for ‘buy’ and ‘sell’ (where buy is the price in which agents would buy from you) The ugly regex is to fix the service’s response which is not valid json but a javascript object literal.



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# File 'lib/crypto_arbitrer.rb', line 68

def fetch_usd_ars
  response = open('http://www.eldolarblue.net/getDolarBlue.php?as=json').read
  rate = JSON.parse(response.gsub(/([{,])([^:]*)/, '\1"\2"') )['exchangerate']
  {'sell' => rate['buy'], 'buy' => rate['sell']}
end

#fetch_usd_vef ⇒ Object

Goes to dolarparalelo.org to grab the actual price for usd to vef The returned hash has ‘sell’ and ‘buy’ keys for the different prices, the prices mean at which price you could buy and sell from them, respectively.



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# File 'lib/crypto_arbitrer.rb', line 92

def fetch_usd_vef
  response = open('http://www.dolarparalelo.org').read
  response =~ /<p><font.*?>Dolar:<\/font>.*?<font.*?>(.*?)</
  rate = $1.to_f
  {'sell' => rate, 'buy' => rate}
end

#parse_btce_prices(response) ⇒ Object 



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# File 'lib/crypto_arbitrer.rb', line 113

def parse_btce_prices(response)
  response =~ /<span id=.max_price..(.*?)..span./
  sell = $1.to_f
  response =~ /<span id=.min_price..(.*?)..span./
  buy = $1.to_f
  {'sell' => sell, 'buy' => buy}
end